private void ParseBNFEntry(string s, ref int x)
{
BNFEntry ret = new BNFEntry();
ParseBNFWhitespace(s, ref x);
BNFEntryReference name = ParseBNFToken(s, ref x);
ret.Name = name.Value;
if (ret.Name.EndsWith(":"))
{
ret.Name = ret.Name.TrimEnd(':');
}
else
{
ParseBNFWhitespace(s, ref x);
if (!BNFMatch(s, ref x, ":"))
{
throw new Exception();
}
}
ParseBNFWhitespace(s, ref x);
bool cont = true;
List <BNFEntryReference> entries = new List <BNFEntryReference>();
while (cont)
{
BNFEntryReference entry = ParseBNFToken(s, ref x);
entries.Add(entry);
ParseBNFWhitespace(s, ref x);
if (BNFMatch(s, ref x, ";"))
{
ret.Children.Add(entries.ToArray());
cont = false;
ParseBNFWhitespace(s, ref x);
}
else if (BNFMatch(s, ref x, "|"))
{
ret.Children.Add(entries.ToArray());
entries = new List <BNFEntryReference>();
ParseBNFWhitespace(s, ref x);
}
}
bnf_entries.Add(ret.Name, ret);
}
private void ParseBNFHeaders(string s, ref int x)
{
ParseBNFWhitespace(s, ref x);
if (BNFMatch(s, ref x, "%token"))
{
ParseBNFWhitespace(s, ref x);
while (!BNFMatch(s, ref x, "%%"))
{
BNFEntryReference tok_name = ParseBNFToken(s, ref x);
tokens.Add(tok_name.Value);
ParseBNFWhitespace(s, ref x);
}
}
ParseBNFWhitespace(s, ref x);
}
private int ParseToken(IList <Preprocessor.token> tokens, int x, BNFEntryReference[] bnr)
{
int orig_x = x;
for (int i = 0; i < bnr.Length; i++)
{
if (x >= tokens.Count)
{
return(orig_x);
}
// Match the token
BNFEntryReference tok = bnr[i];
switch (tok.Type)
{
case BNFEntryReference.type.Constant:
if (tokens[x].value != tok.Value)
{
return(orig_x);
}
x++;
break;
case BNFEntryReference.type.TokenReference:
x++;
break;
case BNFEntryReference.type.EntryReference:
{
int new_x = ParseToken(tokens, x, tok.Value);
if (new_x == x)
{
return(orig_x);
}
x = new_x;
}
break;
}
}
return(x);
}
private BNFEntryReference ParseBNFToken(string s, ref int x)
{
BNFEntryReference ret = new BNFEntryReference();
StringBuilder sb = new StringBuilder();
if (s[x] == '\'')
{
ret.Type = BNFEntryReference.type.Constant;
x++;
while (s[x] != '\'')
{
sb.Append(s[x]);
x++;
}
x++;
ret.Value = sb.ToString();
return(ret);
}
else
{
while (!char.IsWhiteSpace(s[x]))
{
sb.Append(s[x]);
x++;
}
ret.Value = sb.ToString();
if (tokens.Contains(ret.Value))
{
ret.Type = BNFEntryReference.type.TokenReference;
}
else
{
ret.Type = BNFEntryReference.type.EntryReference;
}
return(ret);
}
}
